Stacked piezoelectric vibrator, piezoelectric vibration device, and oven-controlled piezoelectric oscillator

Abstract

To provide a laminated piezoelectric vibrator capable of improving the heat transfer in an OCXO.SOLUTION: A laminated piezoelectric vibrator includes a quartz crystal plate 10, a first sealing member 20, and a second sealing member 30, and a third terminal 23 of the first sealing member 20, which is joined to an oscillation IC 52 by a bonding material, has a non-electrode region R21 and an electrode region R22. An external terminal 32 of the second sealing member 30, which is joined to a heater IC 51 by a bonding material, has a non-electrode region R31 and an electrode region R32. The third terminal 23 and the electrode regions R22, R32 of the external terminal 32 overlap with the seal paths 41, 42 at an outer frame portion 12.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a laminated piezoelectric vibrator, a piezoelectric vibrating device, and an oven-controlled piezoelectric oscillator. [Background technology]

[0002] A piezoelectric vibrator such as a quartz crystal vibrator changes its vibration frequency according to temperature based on its inherent frequency-temperature characteristics. In order to keep the temperature around the piezoelectric vibrator constant, an oven-controlled piezoelectric oscillator (hereinafter, also referred to as "OCXO") is known in which the piezoelectric vibrator is enclosed in a constant temperature oven (see, for example, Patent Document 1).

[0003] In the OCXO described in Patent Document 1, a core section in which an oscillation IC, a piezoelectric vibrator, and a heater IC are stacked is supported inside a heat-insulating package via a flexible core substrate, and the necessary wiring is performed using wire bonding. An OCXO with this configuration enhances the heat insulation effect of the core section while realizing a compact size. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2018 / 097132 Summary of the Invention [Problem to be solved by the invention]

[0005] The OCXO described above uses a three-layered (laminated) piezoelectric vibrator with four external terminals on the bottom surface of the piezoelectric vibrator, which causes problems such as short circuits caused by the bonding material during die bonding and poor heat transfer from the external heating material.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a stacked piezoelectric vibrator capable of improving the heat transfer in an OCXO. Another aim of the present invention is to provide a piezoelectric vibrator device and an OCXO that include such a stacked piezoelectric vibrator. [Means for solving the problem]

[0007] The present invention provides a means for solving the above-mentioned problems as follows: That is, the present invention is a laminated piezoelectric vibrator having a piezoelectric diaphragm in which an outer frame portion, a holding portion, and a vibration portion on which an excitation electrode is formed are integrally formed, a first sealing member covering an upper surface side of the vibration portion, and a second sealing member covering a lower surface side of the vibration portion, characterized in that a heat transfer electrode having a non-electrode region and an electrode region and bonded to an external heating member by a bonding material is formed on an outer surface of the first sealing member or an outer surface of the second sealing member, a ring-shaped first sealing electrode is formed between the first sealing member and the piezoelectric diaphragm, a ring-shaped second sealing electrode is formed between the second sealing member and the piezoelectric diaphragm, and the electrode region of the heat transfer electrode, the first sealing electrode, and the second sealing electrode are overlapped by the outer frame portion.

[0008] According to the above configuration, the electrode area of ​​the heat transfer electrode joined to the external heating member is heated more efficiently than the non-electrode area. Since the electrode area of ​​the heat transfer electrode, the first sealing electrode, and the second sealing electrode are overlapped at the outer frame, the heat of the electrode area of ​​the heat transfer electrode is transferred to the outer frame via the first sealing electrode and the second sealing electrode, and further transferred from the outer frame via the holding part to the vibration part. This makes it possible to improve the heat transfer from the external heating member to the vibration part via the outer frame and the holding part. Therefore, it is possible to provide a stacked piezoelectric vibrator capable of improving the heat transfer in the OCXO.

[0009] In the above configuration, it is preferable that the electrode area of ​​the heat transfer electrode, the first sealing electrode, and the second sealing electrode overlap in an annular shape on the outer frame part. As a result, since the electrode area of ​​the heat transfer electrode, the first sealing electrode, and the second sealing electrode overlap in an annular shape on the outer frame part in a plan view, it is possible to further improve the heat transfer from the external heating member to the vibration part via the outer frame part and the holding part. Therefore, it is possible to provide a stacked piezoelectric vibrator that can improve the heat transfer in the OCXO.

[0010] The present invention also provides a piezoelectric vibration device including the stacked piezoelectric vibrator having the above-mentioned configuration, characterized in that the external heating member is made of an oscillation IC or a heater IC, and is bonded to the outer surface of the stacked piezoelectric vibrator by a bonding material in a state spanning both the non-electrode area and the electrode area of ​​the heat transfer electrode. This improves the bonding strength of the oscillation IC or the heater IC to the piezoelectric vibrator in the piezoelectric vibration device.

[0011] In the above configuration, it is preferable that the multi-layer piezoelectric vibrator is laminated and sandwiched between the oscillation IC and the heater IC. As a result, the oscillation IC and the heater IC transfer heat from both sides of the stacked piezoelectric vibrator to the vibration part of the piezoelectric diaphragm, further improving heat transfer from the oscillation IC and the heater IC to the vibration part of the piezoelectric diaphragm.

[0012] The present invention also provides an oven-controlled piezoelectric oscillator including a piezoelectric vibration device having the above-described configuration, the piezoelectric vibration device being sealed in a heat-insulating package, the core section including at least the oscillation IC, the laminated piezoelectric vibrator, and the heater IC, and at least one of the oscillation IC and the heater IC being laminated on the outer surface of the laminated piezoelectric vibrator, the core section being mounted on the package via a substrate, and a space being provided between the substrate and the inner bottom surface of the package. This space can enhance the heat insulation of the core section, reduce the amount of heat generated by the heater required to maintain the temperature of the core section, and further reduce power consumption.

[0013] In the above configuration, it is preferable that the substrate is mechanically joined to the inner bottom surface of the package at both ends thereof by a bonding material, and the core is electrically joined to the package by a wire, whereby the core is directly mechanically joined to the package, thereby preventing heat from escaping to the outside, and realizing the necessary electrical connection from the core to the outside. Effect of the Invention

[0014] According to the present invention, the electrode area of ​​the heat transfer electrode joined to the external heating member is heated more efficiently than the non-electrode area. Since the electrode area of ​​the heat transfer electrode, the first sealing electrode, and the second sealing electrode overlap at the outer frame, the heat of the electrode area of ​​the heat transfer electrode is transferred to the outer frame via the first sealing electrode and the second sealing electrode, and is further transferred from the outer frame via the holding part to the vibration part. This makes it possible to improve the heat transfer from the external heating member to the vibration part via the outer frame and the holding part. Therefore, it is possible to provide a stacked piezoelectric vibrator capable of improving the heat transfer in the OCXO. [Brief description of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of an OCXO according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view of the OCXO of FIG. [Diagram 3] FIG. 2 is a bottom view of the OCXO of FIG. 1. [Figure 4] 2 is a cross-sectional view showing a schematic configuration of a core section and a core substrate of the OCXO shown in FIG. [Diagram 5] 6 is a schematic diagram showing the configuration of a crystal oscillator in the core portion of FIG. 5. [Figure 6] 2 is a schematic plan view of a first main surface side of a first sealing member of a quartz crystal resonator according to an embodiment of the present invention. FIG. [Figure 7] 4 is a schematic plan view of a second principal surface side of a first sealing member of the quartz crystal unit. FIG. [Figure 8] 2 is a schematic plan view of a first main surface side of a quartz crystal plate of the quartz crystal unit. FIG. [Figure 9] 2 is a schematic plan view of a second main surface side of a quartz crystal plate of a quartz crystal unit. FIG. [Figure 10] 4 is a schematic plan view of a first main surface side of a second sealing member of the quartz crystal unit. FIG. [Figure 11] 4 is a schematic plan view of a second principal surface side of a second sealing member of the quartz crystal unit. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0017] 1 to 3, the OCXO 1 according to this embodiment has a structure in which a core part 5 is disposed inside a recess 2a of a package (housing) 2 made of ceramic or the like and having a substantially H-shaped cross section, and the core part 5 is hermetically sealed by a lid 3. Fig. 2 shows the OCXO 1 with the lid 3 removed, and illustrates the internal structure of the recess 2a of the package 2.

[0018] In detail, as shown in FIG. 1 and FIG. 2, the OCXO 1 has a package 2 with a cross section of a substantially H-shaped shape, in which a recess 2a that is open at the top and a recess 2e that is open at the bottom are formed. A core part 5 is sealed in an airtight state inside the recess 2a of the package 2. A lid 3 is fixed to the upper surface of the peripheral wall part 2b surrounding the recess 2a by seam welding via a sealing material 8, so that the inside of the recess 2a is sealed (airtight). As the sealing material 8, for example, a metal-based sealing material such as an Au-Sn alloy or solder is preferably used, but a sealing material such as low-melting glass may also be used. In addition, it is possible to adopt a configuration of a sealing member by a method such as seam sealing using a metal ring, direct seam sealing without using a metal ring, or beam sealing (seam sealing is preferable in order not to reduce the degree of vacuum). The internal space of the recess 2a is preferably in a high vacuum (for example, a degree of vacuum of 10 Pa or less) or low vacuum atmosphere, or an atmosphere with low thermal conductivity such as low-pressure nitrogen or argon.

[0019] As shown in FIG. 1 and FIG. 3, in the recess 2e formed on the other main surface opposite to the main surface (main surface on which the recess 2a is formed) which is the mounting portion of the core part 5 of the package 2, circuit components such as a capacitor 9 are arranged as adjustment electronic components used in combination with the heater IC 52 of the core part 5. Unlike the recess 2a, the recess 2e does not need to be sealed by the lid 3. In this way, by arranging the circuit components outside the space accommodating the core part 5 of the package 2, it is possible to improve the temperature control of the core part 5 with low power and the temperature tracking ability of the core part 5. In addition, it is possible to prevent the subsequent generation of gas due to solder, flux, etc. in the atmosphere inside the airtightly sealed recess 2a. Therefore, it is preferable to prevent the core part 5 from being adversely affected by the gas and to realize further stabilization of the electrical characteristics.

[0020] In this embodiment, three capacitors 9 are mounted on the other main surface of the package 2 opposite to the one main surface (in this case, the bottom surface of the recess 2e). The capacitors 9 are soldered to mounting pads 9a formed on the bottom surface of the recess 2e of the package 2. The arrangement area of ​​the capacitors 9 is indicated by a dashed line in FIG. 3. A pair of mounting pads 9a, 9a are arranged facing each other along the short side direction of the package 2, and both ends of each of the three capacitors 9 in the short side direction of the package 2 are joined to the mounting pads 9a, 9a. On the lower surface of the package 2, a plurality of external connection terminals 2g (eight in FIG. 3) are also formed for electrically connecting the OCXO 1 to an external circuit board (not shown) provided outside via solder or the like. The number of capacitors 9 mounted on the other main surface of the package 2 is not particularly limited, and the number of capacitors 9 may be other than three. Circuit components other than the capacitors 9 may be mounted on the other main surface of the package 2. The sizes (volume, surface area) of all the circuit components do not have to be the same.

[0021] As shown in FIG. 1 and FIG. 2, a step portion 2c is formed on the inner wall surface of the peripheral wall portion 2b of the recess 2a of the package 2 along the arrangement of a plurality of connection terminals (wire pads) 2h. The core portion 5 is disposed on the bottom surface (inner bottom surface) of the recess 2a between a pair of opposing step portions 2c, 2c via a core substrate (flexible substrate) 4 made of a plate-shaped flexible material. Alternatively, the step portion 2c may be formed so as to surround the bottom surface of the recess 2a on all four sides. The wire pad 2h formed on the step surface of the step portion 2c is connected to the wire pads formed on each component of the core portion 5 by wire bonding via wires 6a and 6b. Specifically, the wire pad 2h of the step portion 2c is connected to the wire pad (see FIG. 2) formed on the oscillation IC 51 of the core portion 5 via the wire 6a. The wire pad 2h of the step portion 2c is connected to the wire pad (see FIG. 2) formed on the heater IC 52 of the core portion 5 via the wire 6b. Also, first and second terminals 21, 22 (see FIG. 5) formed on the crystal resonator 50 of the core portion 5 are connected by wire bonding to wire pads (see FIG. 2) formed on the oscillation IC 51 via wires 6c.

[0022] The core substrate 4 is bonded to the bottom surface of the recess 2a by a non-conductive adhesive (bonding material) 7, and a space (gap) 2d is formed in the lower portion of the core substrate 4. Specifically, a pair of spacer members 2f are provided at a predetermined interval on the bottom surface of the package 2, and a non-conductive adhesive 7 is applied onto each spacer member 2f. The non-conductive adhesive 7 mechanically bonds the core substrate 4 to the bottom surface of the package 2 at both ends of the core substrate 4. The spacer members 2f and the non-conductive adhesive 7 are provided linearly along the short side direction of the core substrate 4 (the direction perpendicular to the paper surface of FIG. 1).

[0023] Furthermore, the bonding area (the area where the non-conductive adhesive 7 is applied) for bonding the core substrate 4 to the package 2 is arranged so as not to overlap with the arrangement area of ​​the core portion 5 on the upper surface of the core substrate 4 in a plan view. The core substrate 4 is made of a resin material having heat resistance and flexibility, such as polyimide. The spacer member 2f is made of a paste material (metallization material) such as molybdenum or tungsten. The non-conductive adhesive 7 may be, for example, a polyimide adhesive or an epoxy adhesive. The core substrate 4 may be made of quartz crystal.

[0024] Next, the core part 5 will be described with reference to FIG. 4. FIG. 4 illustrates the core part 5 mounted on the core substrate 4. The core part 5 is a package of various electronic components used in the OCXO 1, and has a three-layer structure (laminated structure) in which an oscillation IC 51, a crystal oscillator (piezoelectric oscillator) 50, and a heater IC 52 are laminated in this order from the top. The areas of the oscillation IC 51, the crystal oscillator 50, and the heater IC 52 in plan view are gradually reduced toward the top. The core part 5 is configured to stabilize the oscillation frequency of the OCXO 1 by adjusting the temperatures of the crystal oscillator 50, the oscillation IC 51, and the heater IC 52, which have particularly large temperature characteristics. Note that the various electronic components of the core part 5 are not sealed with sealing resin, but may be sealed with sealing resin depending on the sealing atmosphere.

[0025] The crystal oscillator 100 is configured by the crystal resonator 50 and the oscillation IC 51. For example, a VCXO IC can be used as the oscillation IC 51, in which case the crystal oscillator 100 is configured as a VCXO. The oscillation frequency of the OCXO 1 is controlled by controlling the piezoelectric vibration of the crystal resonator 50 with the oscillation IC 51.

[0026] A non-conductive adhesive 53 is interposed between the opposing surfaces of the crystal unit 50 and the oscillation IC 51, and the opposing surfaces of the crystal unit 50 and the oscillation IC 51 are fixed together by the non-conductive adhesive 53. In this case, the top surface of the crystal unit 50 (the first main surface of the first sealing member 20) and the bottom surface of the oscillation IC 51 are joined together via the non-conductive adhesive 53.

[0027] The area of ​​the oscillation IC 51 in a plan view is smaller than that of the crystal unit 50, and the entire oscillation IC 51 is located within the range of the crystal unit 50 in a plan view. The entire bottom surface of the oscillation IC 51 is bonded to the top surface of the crystal unit 50 (the first main surface of the first sealing member 20).

[0028] The heater IC 52 is configured to integrate, for example, a heating element (heat source), a control circuit (current control circuit) for controlling the temperature of the heating element, and a temperature sensor for detecting the temperature of the heating element. By controlling the temperature of the core unit 5 using the heater IC 52, the temperature of the core unit 5 is maintained at a substantially constant temperature, and the oscillation frequency of the OCXO 1 is stabilized. Note that the temperature sensor may be provided as a separate member from the heater IC 52.

[0029] A conductive adhesive 54 is interposed between the opposing surfaces of the crystal unit 50 and the heater IC 52, and the opposing surfaces of the crystal unit 50 and the heater IC 52 are fixed together by the conductive adhesive 54. In this case, the lower surface of the crystal unit 50 (the second main surface of the second sealing member 30) and the upper surface of the heater IC 52 are joined together via the conductive adhesive 54.

[0030] The crystal unit 50 has an area smaller than that of the heater IC 52 in a plan view, and the entire crystal unit 50 is located within the range of the heater IC 52 in a plan view. The entire lower surface of the crystal unit 50 (the second main surface of the second sealing member 30) is bonded to the upper surface of the heater IC 52.

[0031] A non-conductive adhesive 55 is interposed between the opposing surfaces of the heater IC 52 and the core substrate 4, and the opposing surfaces of the heater IC 52 and the core substrate 4 are fixed to each other by the non-conductive adhesive 55. As the non-conductive adhesives 53 and 55 and the conductive adhesive 54, for example, a polyimide adhesive, an epoxy adhesive, or the like is used.

[0032] In the core section 5 shown in FIG. 5, wire pads for wire bonding (see FIG. 2) are formed on the upper surfaces of the oscillation IC 51, the crystal unit 50, and the heater IC 52. The wire bonding of the oscillation IC 51, the crystal unit 50, and the heater IC 52 is not performed before the core section 5 is mounted on the package 2, but is performed after the core section 5 (core substrate 4) is mounted on the package 2. That is, as shown in FIG. 1 and FIG. 2, after the core section 5 (core substrate 4) is mounted on the package 2, the wire pad formed on the upper surface of the crystal unit 50 is connected to the wire pad formed on the oscillation IC 51 via the wire 6c. The wire pad formed on the oscillation IC 51 is connected to the wire pad 2h formed on the step surface of the step section 2c via the wire 6a. The wire pad formed on the upper surface of the heater IC 52 is connected to the wire pad 2h formed on the step surface of the step section 2c via the wire 6b. In this way, by performing wire bonding after mounting the core unit 5 on the package 2, the wire bonding can be performed efficiently, and the OCXO 1 with excellent mass productivity can be provided.

[0033] Thus, in this embodiment, the core unit 5 is supported by the package 2 via the core substrate 4, and the core unit 5 has at least the oscillation IC 51, the crystal unit 50, and the heater IC 52, and is configured to be stacked in this order: the oscillation IC 51, the crystal unit 50, and the heater IC 52. The heater IC 52 controls the current supplied to the heating element to adjust the temperature of the core unit 5, thereby maintaining the temperature of the core unit 5 at a substantially constant temperature.

[0034] The type of quartz crystal unit 50 used in the core portion 5 is not particularly limited, but a stacked quartz crystal unit, which is easy to make the device thinner, can be preferably used. The stacked quartz crystal unit is a three-layered device that is composed of first and second sealing members made of glass or quartz crystal, and a piezoelectric diaphragm made of, for example, quartz crystal and having a vibration part with excitation electrodes formed on both main surfaces, in which the first sealing member and the second sealing member are stacked and bonded via the piezoelectric diaphragm, and the vibration part of the piezoelectric diaphragm arranged inside is hermetically sealed.

[0035] An example of a crystal oscillator 100 in which a crystal resonator 50 as such a multi-layer crystal resonator and an oscillation IC (eg, an IC for VCXO) 51 are integrally provided will be described with reference to FIGS. 5 to 11. FIG.

[0036] As shown in Fig. 5, the crystal oscillator 100 is configured to include a crystal vibration plate (piezoelectric vibration plate) 10, a first sealing member 20, a second sealing member 30, and an oscillation IC 51. In this crystal oscillator 100, the crystal vibration plate 10 and the first sealing member 20 are bonded together, and the crystal vibration plate 10 and the second sealing member 30 are bonded together to form a package with a substantially rectangular sandwich structure. That is, in the crystal oscillator 100, the first sealing member 20 and the second sealing member 30 are bonded to both main surfaces of the crystal vibration plate 10 to form an internal space (cavity) of the package, and the vibration part 11 (see Figs. 8 and 9) is hermetically sealed in this internal space.

[0037] The crystal oscillator 100 has a package size of, for example, 1.0×0.8 mm, and is small and low-profile. In addition, in order to achieve the small size, the package does not form castellations, but uses through-holes to provide electrical continuity between the electrodes. The oscillation IC 51 mounted on the first sealing member 20 is a one-chip integrated circuit element that, together with the crystal vibration plate 10, constitutes an oscillation circuit. The crystal oscillator 100 is mounted on the heater IC 52 described above via a conductive adhesive 54.

[0038] As shown in Figs. 8 and 9, the quartz crystal vibrating plate 10 is a piezoelectric substrate made of quartz crystal, and both of its main surfaces (first main surface 101, second main surface 102) are formed as flat and smooth surfaces (mirror-finished). An AT-cut quartz crystal plate that performs thickness-shear vibration is used as the quartz crystal vibrating plate 10. In the quartz crystal vibrating plate 10 shown in Figs. 8 and 9, both main surfaces 101, 102 of the quartz crystal vibrating plate 10 are in the XZ' plane. In this XZ' plane, the direction parallel to the short side direction (short side direction) of the quartz crystal vibrating plate 10 is the X-axis direction, and the direction parallel to the long side direction (long side direction) of the quartz crystal vibrating plate 10 is the Z'-axis direction.

[0039] A pair of excitation electrodes (first excitation electrode 111, second excitation electrode 112) are formed on both main surfaces 101, 102 of the quartz crystal vibration plate 10. The quartz crystal vibration plate 10 has a vibration part 11 formed in a substantially rectangular shape, an outer frame part 12 surrounding the outer periphery of the vibration part 11, and a holding part (connecting part) 13 that holds the vibration part 11 by connecting the vibration part 11 and the outer frame part 12. In other words, the quartz crystal vibration plate 10 is configured such that the vibration part 11, the outer frame part 12, and the holding part 13 are integrally provided. The holding part 13 extends (protrudes) in the -Z' direction from only one corner of the vibration part 11 located in the +X direction and the -Z' direction to the outer frame part 12.

[0040] The first excitation electrode 111 is provided on the first main surface 101 side of the vibration section 11, and the second excitation electrode 112 is provided on the second main surface 102 side of the vibration section 11. The first excitation electrode 111 and the second excitation electrode 112 are connected with lead-out wiring (first lead-out wiring 113, second lead-out wiring 114) for connecting these excitation electrodes to external electrode terminals. The first lead-out wiring 113 is led out from the first excitation electrode 111 and connected to a connection bonding pattern 14 formed on the outer frame section 12 via a holding section 13. The second lead-out wiring 114 is led out from the second excitation electrode 112 and connected to a connection bonding pattern 15 formed on the outer frame section 12 via a holding section 13.

[0041] A vibration-side sealing portion for bonding the quartz crystal plate 10 to the first sealing member 20 and the second sealing member 30 is provided on both main surfaces (first main surface 101 and second main surface 102) of the quartz crystal plate 10. A vibration-side first bonding pattern 121 is formed as the vibration-side sealing portion on the first main surface 101, and a vibration-side second bonding pattern 122 is formed as the vibration-side sealing portion on the second main surface 102. The vibration-side first bonding pattern 121 and the vibration-side second bonding pattern 122 are provided on the outer frame portion 12 and are formed in annular shapes in a plan view.

[0042] As shown in Figs. 8 and 9, the quartz crystal vibration plate 10 has five through holes penetrating between the first main surface 101 and the second main surface 102. Specifically, the four first through holes 161 are provided in the four corners (corner portions) of the outer frame portion 12. The second through hole 162 is provided in the outer frame portion 12 on one side in the Z'-axis direction of the vibration portion 11 (the -Z'-direction side in Figs. 8 and 9). Around the first through hole 161, a vibration-side first bonding pattern 121 is formed on the first main surface 101 side, and a vibration-side second bonding pattern 122 is formed on the second main surface 102 side. Around the second through hole 162, a connection bonding pattern 124 is formed on the first main surface 101 side, and a connection bonding pattern 15 is formed on the second main surface 102 side.

[0043] In the first through-hole 161 and the second through-hole 162, a through electrode for achieving electrical continuity between the electrodes formed on the first main surface 101 and the second main surface 102 is formed along the inner wall surface of each through-hole. In addition, the central portion of each of the first through-hole 161 and the second through-hole 162 is a hollow through portion that penetrates between the first main surface 101 and the second main surface 102.

[0044] Next, as shown in Figures 6 and 7, the first sealing member 20 is a rectangular parallelepiped substrate formed from a single AT-cut quartz crystal plate, and the second main surface 202 (the surface to be bonded to the quartz crystal vibration plate 10) of this first sealing member 20 is formed as a flat and smooth surface (mirror-finished). Although the first sealing member 20 does not have a vibrating part, by using an AT-cut quartz crystal plate like the quartz crystal vibration plate 10, the thermal expansion coefficients of the quartz crystal vibration plate 10 and the first sealing member 20 can be made the same, and thermal deformation in the quartz crystal oscillator 100 can be suppressed. The directions of the X-axis, Y-axis, and Z'-axis in the first sealing member 20 are also the same as those of the quartz crystal vibration plate 10.

[0045] As shown in FIG. 6, the first sealing member 20 has a first and second terminals 21 and 22 for wiring formed on the outer surface of the package and a third terminal 23 for shielding (for earth connection) formed on the first main surface 201 (the main surface not facing the crystal vibration plate 10) formed on the first sealing member 20. The first and second terminals 21 and 22 are connected to a wire pad (see FIG. 2) formed on the oscillation IC 51 by wire bonding via a wire 6c. The first terminal 21 is electrically connected to the first excitation electrode 111 of the crystal vibration plate 10. The second terminal 22 is electrically connected to the second excitation electrode 112 of the crystal vibration plate 10. The first and second terminals 21 and 22 are provided at both ends in the Z′-axis direction, with the first terminal 21 provided on the +Z′-direction side and the second terminal 22 provided on the −Z′-direction side.

[0046] The third terminal 23 is provided in the four corners (corners) and the central region of the first main surface 201 of the first sealing member 20, and is substantially H-shaped. The third terminal 23 is disposed at a predetermined interval from the first and second terminals 21 and 22, and is provided in almost all of the region of the first main surface 201 of the first sealing member 20 where the first and second terminals 21 and 22 are not formed. An oscillation IC 51 is mounted on the upper side of the third terminal 23 via a non-conductive adhesive 53. The third terminal 23 is electrically connected to the external terminal 32 formed on the second main surface 302 of the second sealing member 30, and is connected to earth. The third terminal 23 does not necessarily have to be connected to earth, in other words, the third terminal does not have to have an electrical connection function.

[0047] As shown in Fig. 6 and Fig. 7, six through holes are formed in the first sealing member 20 penetrating between the first main surface 201 and the second main surface 202. Specifically, four third through holes 211 are provided in the four corner (corner) regions of the first sealing member 20. The fourth and fifth through holes 212 and 213 are provided in the +Z' direction and -Z' direction in Fig. 6 and Fig. 7, respectively.

[0048] In the third through-hole 211 and the fourth and fifth through-holes 212, 213, a through electrode for achieving electrical continuity between the electrodes formed on the first main surface 201 and the second main surface 202 is formed along the inner wall surface of each through-hole. In addition, the central portions of the third through-hole 211 and the fourth and fifth through-holes 212, 213 each form a hollow through portion that penetrates between the first main surface 201 and the second main surface 202.

[0049] A sealing-side first bonding pattern 24 is formed on the second main surface 202 of the first sealing member 20 as a sealing-side first sealing portion for bonding to the quartz crystal vibration plate 10. The sealing-side first bonding pattern 24 is formed in a ring shape in a plan view. The sealing-side first bonding pattern 24 is also formed around each of the third through holes 211. A connection bonding pattern 262 is formed around the fourth through hole 212, and a connection bonding pattern 261 is formed around the fifth through hole 213. Furthermore, a connection bonding pattern 263 is formed on the opposite side (-Z' direction side) of the connection bonding pattern 261 in the long axis direction of the first sealing member 20, and the connection bonding pattern 261 and the connection bonding pattern 263 are connected by a wiring pattern 27.

[0050] 10 and 11, the second sealing member 30 is a rectangular parallelepiped substrate formed from a single AT-cut quartz crystal plate, and a first main surface 301 (the surface to be bonded to the quartz crystal vibration plate 10) of this second sealing member 30 is formed as a flat and smooth surface (mirror-finished). Note that, like the quartz crystal vibration plate 10, the second sealing member 30 also uses an AT-cut quartz crystal plate, and it is preferable that the orientations of the X-axis, Y-axis, and Z'-axis are the same as those of the quartz crystal vibration plate 10.

[0051] A sealing-side second bonding pattern 31 is formed on the first main surface 301 of the second sealing member 30 as a sealing-side second sealing portion for bonding to the quartz crystal vibration plate 10. The sealing-side second bonding pattern 31 is formed in a ring shape in a plan view. The sealing-side second bonding pattern 31 is also formed around a sixth through-hole 33, which will be described later.

[0052] The external terminal 32 is formed in a ring shape on the second main surface 302 of the second sealing member 30, and is formed on substantially the entire surface except for a substantially circular portion in the center. The external terminal 32 is also formed around a sixth through hole 33, which will be described later.

[0053] As shown in FIG. 10 and FIG. 11, the second sealing member 30 has one sixth through hole 33 penetrating between the first main surface 301 and the second main surface 302. The sixth through hole 33 is provided in the region of the four corners (corner portions) of the second sealing member 30. In the sixth through hole 33, a through electrode for achieving electrical continuity between the electrodes formed on the first main surface 301 and the second main surface 302 is formed along the inner wall surface of each sixth through hole 33. In addition, the center portion of each sixth through hole 33 is a hollow through portion penetrating between the first main surface 301 and the second main surface 302. Note that, when the third terminal 23 of the first sealing member 20 is not connected to earth, the sixth through hole 33 may not be provided in the second sealing member 30.

[0054] In the crystal oscillator 100 including the crystal vibration plate 10, the first sealing member 20, and the second sealing member 30 configured as above, the crystal vibration plate 10 and the first sealing member 20 are diffusion bonded with the vibration-side first bonding pattern 121 and the sealing-side first bonding pattern 24 overlapping each other, and the crystal vibration plate 10 and the second sealing member 30 are diffusion bonded with the vibration-side second bonding pattern 122 and the sealing-side second bonding pattern 31 overlapping each other, to manufacture a sandwich-structured package as shown in Fig. 5. This hermetically seals the internal space of the package, i.e., the space housing the vibration part 11.

[0055] At this time, the above-mentioned connection bonding patterns are also diffusion bonded in a state of being overlapped with each other. The connection bonding patterns are bonded to each other to obtain electrical conduction in the crystal oscillator 100. Specifically, the first excitation electrode 111 is connected to the oscillation IC 51 via the first lead wiring 113, the wiring pattern 27, the fourth through hole 212, the first terminal 21, and the wire 6c in this order. The second excitation electrode 112 is connected to the oscillation IC 51 via the second lead wiring 114, the second through hole 162, the fifth through hole 213, the second terminal 22, and the wire 6c in this order.

[0056] In the crystal oscillator 100, the various bonding patterns are preferably formed by laminating multiple layers on the crystal plate, with a Ti (titanium) layer and an Au (gold) layer formed from the bottom layer side by vapor deposition or sputtering. In addition, if the other wiring and electrodes formed on the crystal oscillator 100 have the same configuration as the bonding patterns, the bonding patterns, wiring, and electrodes can be patterned simultaneously, which is preferable.

[0057] In the crystal oscillator 100 configured as described above, the sealing electrodes (seal paths) 41, 42 that hermetically seal the vibration part 11 of the crystal vibration plate 10 are formed in an annular shape in a plan view. The seal path 41 as the first sealing electrode is formed by diffusion bonding the above-mentioned vibration-side first bonding pattern 121 and the sealing-side first bonding pattern 24, and the outer and inner edge shapes of the seal path 41 are formed in a substantially rectangular shape. Similarly, the seal path 42 as the second sealing electrode is formed by diffusion bonding the above-mentioned vibration-side second bonding pattern 122 and the sealing-side second bonding pattern 31, and the outer and inner edge shapes of the seal path 42 are formed in a substantially rectangular shape. The seal paths 41, 42 are not electrically connected to the wiring connected to the above-mentioned first and second excitation electrodes 111, 112. On the other hand, the seal paths 41, 42 are electrically connected to the third terminal 23 of the first sealing member 20 and the external terminal 32 of the second sealing member 30 via the through electrode in the first through hole 161, the through electrode in the third through hole 211, and the through electrode in the sixth through hole 33. The external terminal 32 is connected to the heater IC 52 via a conductive adhesive 54, so that the seal paths 41, 42 and the third terminal 23 are earthed.

[0058] In this embodiment, the quartz crystal resonator 50 is a laminated quartz crystal resonator in which the first sealing member 20, the quartz crystal plate 10, and the second sealing member 30 are laminated, and the third terminal 23 is formed on the outer surface of the first sealing member 20 as a top heat transfer electrode bonded to the heating external member (oscillation IC 51) by a bonding material, and the external terminal 32 is formed on the outer surface of the second sealing member 30 as a bottom heat transfer electrode bonded to the heating external member (heater IC 52) by a bonding material, and the third terminal 23 and the external terminal 32 have non-electrode areas R21, R31 and electrode areas R22, R32, and the electrode areas R22, R32 of the third terminal 23 and the external terminal 32 and the seal paths 41, 42 as sealing electrodes are annularly overlapped with the outer frame portion 12 in a plan view. This point will be described below with reference to Figs. 5 to 11.

[0059] The third terminal 23 as an upper heat transfer electrode formed on the first main surface 201 of the first sealing member 20 is bonded to the oscillation IC 51 as an external heating member by a bonding material (non-conductive adhesive 53). As shown in FIG. 6, the third terminal 23 is substantially H-shaped, and has a non-electrode region (region where no electrode is formed) R21 overlapping a part of the vibration part 11 of the quartz crystal vibration plate 10, and an electrode region (region where an electrode is formed) R22 overlapping a part of the outer frame part 12 of the quartz crystal vibration plate 10. Specifically, the space between the central region of the third terminal 23 and the first and second terminals 21 and 22 is the non-electrode region R21, and the two sides of the third terminal 23 facing each other in the X-axis direction are the electrode regions R22. The area of ​​the third terminal 23 in a plan view is formed to be 50% or more of the area of ​​the first sealing member 20 in a plan view. The third terminal 23 and the sealing paths 41, 42 are electrically connected via a through electrode in the first through hole 161 as a connection electrode, a through electrode in the third through hole 211, and a through electrode in the sixth through hole 33, and the third terminal 23 and the sealing paths 41, 42 are thermally coupled.

[0060] In addition, the external terminal 32 as a bottom heat transfer electrode formed on the second main surface 302 of the second sealing member 30 is bonded to the heater IC 52 as a heating external member by a bonding material (conductive adhesive 54). As shown in FIG. 11, the external terminal 32 is formed in an annular shape with a substantially circular space in the center, and this space is a non-electrode area (area where no electrodes are formed) R31 that overlaps with the vibration part 11 of the quartz crystal vibration plate 10. In addition, the annular part of the external terminal 32 other than the substantially circular space is an electrode area (area where electrodes are formed) R32 that overlaps with the outer frame part 12 of the quartz crystal vibration plate 10. The electrode area R32 of the external terminal 32 overlaps with the entire outer frame part 12 of the quartz crystal vibration plate 10 in a plan view. The area of ​​the external terminal 32 in a plan view is formed to be 50% or more of the area of ​​the second sealing member 30 in a plan view. The external terminal 32 and the seal paths 41, 42 are electrically connected through the through electrode in the third through hole 211 as a connection electrode and the through electrode in the sixth through hole 33, and the external terminal 32 and the seal paths 41, 42 are thermally coupled. The external terminal 32 and the seal paths 41, 42 are annularly overlapped with the outer frame portion 12 in a plan view. Here, the electrode configuration of the outer surface of the quartz crystal unit 50 (the third terminal 23 as the upper heat transfer electrode, the external terminal 32 as the bottom heat transfer electrode, etc.) is a laminated configuration including, for example, a Ti film, a NiTi film, and an Au film, and the electrode configuration of the quartz crystal plate 10 and the first and second sealing members 20, 30 inside the quartz crystal unit 50 is a laminated configuration including, for example, a Ti film and an Au film. In addition, the Ti film of the electrode configuration of the quartz crystal plate 10 is thinner than the Ti film of the electrode configuration of the first and second sealing members 20, 30. The electrodes may be made of other film materials or laminates than those mentioned above.

[0061] According to this embodiment, the third terminal 23 of the first sealing member 20 is heated by the oscillation IC 51, and the external terminal 32 of the second sealing member 30 is heated by the heater IC 52. In this case, the electrode regions R22, R32 of the third terminal 23 and the external terminal 32 are heated more efficiently than the non-electrode regions R21, R31. Since the electrode regions R22, R32 of the third terminal 23 and the external terminal 32 heated by the oscillation IC 51 and the heater IC 52 and the seal paths 41, 42 overlap with the outer frame portion 12 in a plan view, the heat of the electrode regions R22, R32 of the third terminal 23 and the external terminal 32 is transferred to the outer frame portion 12 via the seal paths 41, 42, and further transferred from the outer frame portion 12 to the vibration portion 11 via the holding portion 13. This improves the heat transfer from the oscillation IC 51 and the heater IC 52 to the vibration part 11 via the outer frame part 12 and the holding part 13 of the quartz crystal vibration plate 10. In addition, since the electrode region R32 of the external terminal 32 and the seal paths 41 and 42 are annularly overlapped with the outer frame part 12 in a plan view, it is possible to further improve the heat transfer from the heater IC 52 to the vibration part 11 via the outer frame part 12 and the holding part 13 of the quartz crystal vibration plate 10. Therefore, it is possible to provide a stacked piezoelectric vibrator that can improve the heat transfer in the OCXO 1.

[0062] In this embodiment, the third terminal 23 and the external terminal 32 are provided on both the first main surface 201 of the first sealing member 20 and the second main surface 302 of the second sealing member 30, which further improves heat transfer from the oscillation IC 51 and the heater IC 52 to the vibration part 11 of the quartz crystal vibration plate 10. In addition, the external terminal 32 and the heater IC 52 are bonded together with a conductive adhesive 54, which improves heat transfer from the heater IC 52 to the vibration part 11 of the quartz crystal vibration plate 10 compared to when a non-conductive adhesive is used.

[0063] In this embodiment, the third terminal 23 overlaps with the portions of the sealing paths 41, 42 formed on at least two sides of the outer frame portion 12 in a plan view. Specifically, the third terminal 23 overlaps with the portions of the sealing paths 41, 42 formed on two sides facing each other in the X-axis direction in a plan view. Also, the external terminal 32 overlaps with the portions of the sealing paths 41, 42 formed on at least two sides of the outer frame portion 12 in a plan view. Specifically, the external terminal 32 overlaps with the entire periphery of the sealing paths 41, 42 (two sides facing each other in the X-axis direction and two sides facing each other in the Z'-axis direction) in a plan view. This positional relationship can improve the heat transfer from the oscillation IC 51 and the heater IC 52 to the vibration portion 11 of the quartz crystal vibration plate 10.

[0064] Moreover, the third terminal 23 and the external terminal 32 are connected to the heater IC 52 via a conductive adhesive 54, and are connected to a ground power supply. This ensures a shielding function provided by the third terminal 23 and the external terminal 32, and reduces the influence of external noise.

[0065] In this embodiment, the center of gravity (center) of the third terminal 23 and the center of gravity (center) of the first sealing member 20 are approximately aligned. Also, the center of gravity (center) of the external terminal 32 and the center of gravity (center) of the second sealing member 30 are approximately aligned. This positional relationship allows efficient heat transfer from the oscillation IC 51 and the heater IC 52 to the vibration part 11 of the quartz crystal vibration plate 10.

[0066] In addition, since the area of ​​the third terminal 23 in a planar view is 50% or more of the area of ​​the first sealing member 20 in a planar view, and the area of ​​the external terminal 32 in a planar view is 50% or more of the area of ​​the second sealing member 30 in a planar view, the heat transfer from the oscillation IC 51 and the heater IC 52 to the vibration part 11 of the quartz vibration plate 10 can be further improved.

[0067] Here, the third terminal 23 may be formed in a ring shape having a substantially circular space in the center, similar to the external terminal 32. In this case, the substantially circular space in the center of the third terminal 23 becomes a non-electrode area (area where no electrodes are formed) R21 that overlaps with the vibration part 11 of the quartz crystal vibration plate 10, and the ring-shaped part of the third terminal 23 other than the substantially circular space becomes an electrode area (area where electrodes are formed) R22 that overlaps with the outer frame part 12 of the quartz crystal vibration plate 10. The electrode area R22 of the third terminal 23 overlaps with the entire outer frame part 12 of the quartz crystal vibration plate 10 in a planar view. According to this configuration, not only the electrode area R32 and the seal paths 41 and 42 of the external terminal 32 but also the electrode area R22 of the third terminal 23 overlaps with the outer frame part 12 in a ring shape in a planar view, so that heat from the oscillation IC 51 and the heater IC 52 can be more efficiently transferred to the vibration part 11 of the quartz crystal vibration plate 10 through the outer frame part 12. The electrode area of ​​the third terminal 23 and the non-electrode areas R21, R31 of the external terminal 32 may be rectangular or have another shape. The electrode area of ​​the third terminal 23 and the non-electrode areas R21, R31 of the external terminal 32 may be formed in a mesh shape, or may have a shape in which there are both sparse and dense parts of the metal film (thickness of the metal film is small and thick).

[0068] In the crystal oscillator (piezoelectric vibration device) 100 having the crystal unit 50 configured as described above, the heating external members are the oscillation IC 51 and the heater IC 52, which are bonded to the outer surface of the crystal unit 50 by a bonding material while spanning both the non-electrode area and the electrode area of ​​the heat transfer electrodes (third terminal 23, external terminal 32). Specifically, the oscillation IC 51 is bonded by a non-conductive adhesive 53 while spanning both the non-electrode area R21 and the electrode area R22 of the third terminal 23 of the first sealing member 20 of the crystal unit 50. The heater IC 52 is bonded by a conductive adhesive 54 while spanning both the non-electrode area R31 and the electrode area R32 of the external terminal 32 of the second sealing member 30 of the crystal unit 50. This improves the bonding strength of the oscillation IC 51 and the heater IC 52 to the crystal unit 50 by the bonding material. Here, because the electrode region R32 of the external terminal 32 is formed in a ring shape, the adhesive strength between the central non-electrode region R31 (quartz crystal base portion) and the conductive adhesive 54 (resin adhesive) is strong, and the adhesive strength between the peripheral electrode region R32 (metal film portion) and the conductive adhesive 54 is weak. This makes it possible to weaken the stress of the conductive adhesive 54 in the region overlapping the outer frame portion 12 of the quartz crystal vibrating plate 10, and to prevent unnecessary stress from being applied to the sealing portion of the quartz crystal vibrating plate 10. The same effect can be obtained by forming the electrode region R22 of the third terminal 23 in a ring shape.

[0069] In this embodiment, the crystal unit 50 is sandwiched between the oscillation IC 51 and the heater IC 52 and stacked. This allows the oscillation IC 51 and the heater IC 52 to transfer heat from both sides of the crystal unit 50 to the vibration part 11 of the crystal plate 10, thereby further improving the heat transfer from the oscillation IC 51 and the heater IC 52 to the vibration part 11 of the crystal plate 10.

[0070] In the OCXO1 equipped with the crystal oscillator 100 of the above configuration, the crystal oscillator 100 is sealed in a heat-insulating package 2, the core section 5 includes at least an oscillation IC 51, a crystal unit 50, and a heater IC 52, and at least one of the oscillation IC 51 and the heater IC 52 is laminated on the outer surface of the crystal unit 50, the core section 5 is mounted on the package 2 via a core substrate 4, and a space 2d is provided between the core substrate 4 and the inner bottom surface of the package 2. This allows the space 2d to enhance the heat insulation of the core section 5, and the amount of heat generated by the heater required to maintain the temperature of the core section 5 to be reduced, thereby further reducing the power consumption of the OCXO1.

[0071] In the present embodiment, in the OCXO 1, the core substrate 4 is mechanically joined at both ends of the core substrate 4 to the inner bottom surface of the package 2 by a bonding material, and the core unit 5 is electrically joined to the package 2 by wires 6a and 6b. This makes it possible to prevent heat from escaping to the outside by directly mechanically joining the core unit 5 to the package 2, and also to realize the necessary electrical connection from the core unit 5 to the outside.

[0072] In this embodiment, the crystal unit 50 is only connected to the oscillation IC 51 via the wire 6c, and the crystal unit 50 is not directly wire-connected to the package 2. This configuration can prevent heat from escaping from the crystal unit 50 to the package 2 through the wire. As a result, there are advantages in that the insulation of the crystal unit 50 is improved, and the temperature controllability of the crystal unit 50 is improved. In addition, by making the wire diameter of the wire 6c connected to the crystal unit 50 smaller than the wire diameter of the wires 6a and 6b not connected to the crystal unit 50, it is possible to prevent heat from the crystal unit 50 from escaping to the outside. In addition, by making the thickness of the second sealing member 30 on the heater IC 52 side of the crystal unit 50 larger than the thicknesses of the crystal plate 10 and the first sealing member 20, it is possible to prevent heat from the crystal unit 50 from escaping to the outside. Furthermore, a highly thermally conductive film or a photosensitive polyimide film may be interposed between the heater IC 51 and the crystal unit 50 as a bonding material, thereby preventing the heat of the crystal unit 50 from escaping to the outside.

[0073] In this embodiment, in the OCXO 1, the bonded region of the core substrate 4 by the non-conductive adhesive 7 (the region mechanically bonded to the inner bottom surface of the recess 2a of the package 2) does not overlap with the arrangement region of the core portion 5 on the core substrate 4 in a plan view. As a result, the arrangement region of the core portion 5 and the bonded region are not provided continuously across the core substrate 4, so that it is possible to prevent heat from the core portion 5 from escaping to the outside via the bonded region (non-conductive adhesive 7). In addition, the core portion 5 is vacuum-sealed inside the package 2, which makes it easier to prevent heat from escaping from the core portion 5.

[0074] In addition, in the OCXO 1, the spacer member 2f and the non-conductive adhesive 7 are arranged vertically stacked, which makes it easy to ensure the space 2d between the core substrate 4 and the inner bottom surface of the package 2. Note that the spacer member 2f and the non-conductive adhesive 7 may be arranged side by side, or the spacer member 2f may be stacked vertically in two stages.

[0075] The embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present invention is not interpreted solely by the above-described embodiments, but is defined by the claims. Also, all modifications within the scope and meaning equivalent to the claims are included.

[0076] In the above embodiment, the heat transfer electrodes (third terminal 23, external terminal 32) are provided on both the outer surface of the first sealing member 20 and the outer surface of the second sealing member 30, but the present invention is not limited to this. Heat transfer electrodes may be provided only on one of the outer surfaces of the first sealing member 20 and the second sealing member 30. In addition, both the heat transfer electrodes of the first sealing member 20 and the heat transfer electrodes of the second sealing member 30 may be provided with a non-electrode area (area where no electrode is formed) that overlaps with a part of the vibration part 11 of the quartz vibration plate 10 and an electrode area (area where an electrode is formed) that overlaps with a part of the outer frame part 12 of the quartz vibration plate 10, or only one of the heat transfer electrodes of the first sealing member 20 and the second sealing member 30 may be provided with a non-electrode area (area where no electrode is formed) that overlaps with a part of the vibration part 11 of the quartz vibration plate 10 and an electrode area (area where an electrode is formed) that overlaps with a part of the outer frame part 12 of the quartz vibration plate 10.

[0077] The shapes and sizes of the third terminal 23 and the external terminal 32 described above are merely examples and can be modified in various ways. For example, the third terminal 23 may be formed on substantially the entire surface of the first main surface 201 of the first sealing member 20. In addition, the third terminal 23 is formed to have a substantially H-shape including two opposing sides and a center of gravity, but is not limited thereto, and the third terminal 23 may be formed to have a T-shape, a Z-shape, a ring shape, a figure-8 shape, or the like. In addition, when the third terminal 23 is formed in a ring shape, the external terminal 32 may be formed on substantially the entire surface of the second main surface 302 of the second sealing member 30.

[0078] In the above embodiment, the core unit 5 is configured such that at least the IC 51 for oscillation, the crystal unit 50, and the IC 52 for heater are stacked in this order from the top, but conversely, the core unit 5 may be configured such that at least the IC 52 for heater, the crystal unit 50, and the IC 51 for oscillation are stacked in this order from the top. Note that the core unit 5 may be configured such that at least the IC 51 for oscillation, the IC 52 for heater, and the crystal unit 50 are stacked in this order from the top, and in this configuration, a crystal unit 50 of a relatively large size can be used, and the characteristics required for the crystal unit 50 can be easily ensured.

[0079] The core unit 5 may have a structure in which at least the oscillation IC 51, the crystal unit 50, and the heater IC 52 are stacked in order, and may have a structure in which, for example, a heater substrate or the like is added to the stacked structure of the oscillation IC 51, the crystal unit 50, and the heater IC 52. For example, a four-layer structure in which the heater substrate, the oscillation IC 51, the crystal unit 50, and the heater IC 52 are stacked in order from the top may be used, or a four-layer structure in which the heater IC 52, the crystal unit 50, the oscillation IC 51, and the heater substrate may be stacked in order from the top. In these cases, the temperature of the core unit 5 can be made more uniform by stacking the heater substrate, which is a heating element, on the oscillation IC 51.

[0080] Furthermore, the core unit 5 may not have the laminated structure as described above as long as it has at least the oscillation IC 51, the crystal unit 50, and the heater IC 52. For example, the core unit 5 may have a heater substrate, a plurality of chip capacitors (bypass capacitors), and the like, in addition to the oscillation IC 51, the crystal unit 50, and the heater IC 52. In this case, the bonding area between the core substrate 4 and a component (e.g., the heater substrate) directly bonded to the core substrate 4 is the area where the core unit 5 is provided.

[0081] In the above embodiment, the core unit 5 and the package 2 are electrically connected without passing through the core substrate 4. However, the core unit 5 and the package 2 may be electrically connected through the core substrate 4.

[0082] In the above embodiment, the core unit 5 is configured such that the crystal unit 50 is mounted on the heater IC 52, and the oscillation IC 51 is mounted on the crystal unit 50. However, the present invention is not limited to this, and the core unit 5 may be configured such that the crystal unit 50 and the oscillation IC 51 are mounted horizontally on the heater IC 52.

[0083] In the above embodiment, an AT-cut quartz crystal plate is used as the quartz crystal plate 10, but other quartz crystal plates (e.g., an SC-cut quartz crystal plate, a quartz crystal Z plate, etc.) may be used. In addition, the first sealing member 20 and the second sealing member 30 are formed from quartz crystal plates, but this is not limiting, and the first sealing member 20 and the second sealing member 30 may be formed from, for example, glass or resin.

[0084] In the above embodiment, the crystal unit 50 as a laminated piezoelectric vibrator is applied to the OCXO 1. However, the laminated piezoelectric vibrator is not limited to this, and may be applied to, for example, a piezoelectric vibrator with a temperature sensor (TSX, etc.) equipped with a temperature sensor such as a thermistor, or may be applied to a temperature-compensated piezoelectric oscillator (TCXO, etc.) in which a temperature compensation circuit is added to a piezoelectric oscillator. In these piezoelectric vibrators with a temperature sensor and temperature-compensated piezoelectric oscillators, the heat transfer between the laminated piezoelectric vibrator and the temperature sensor or IC is improved, making it difficult for a temperature difference to occur between them, which contributes to improving electrical characteristics. [Explanation of symbols]

[0085] 1 OCXO (oven-controlled piezoelectric oscillator) 2 Package 4 Core Board 5 Core 10 Crystal diaphragm 11 Vibration section 12 Outer frame 13 Holding part 20 First sealing member 23 Third terminal (top heat transfer electrode) 30 Second sealing member 32 External terminal (bottom heat transfer electrode) 41 Seal path (first sealing electrode) 42 Seal path (second sealing electrode) 50 Quartz crystal unit (laminated piezoelectric unit) 51 Oscillation IC (external heating component) 52 Heater IC (external heating component) 100 Crystal Oscillator (Piezoelectric Vibration Device) 111 1st excitation electrode 112 2nd excitation electrode R21, R31 Non-electrode area R22, R32 electrode area

Claims

1. a piezoelectric diaphragm having an outer frame, a holding portion, and a vibration portion having an excitation electrode formed thereon, which are integrally formed; A first sealing member covering an upper surface side of the vibration portion; a second sealing member covering a lower surface side of the vibration portion, a heat transfer electrode is formed on an outer surface of the first sealing member or an outer surface of the second sealing member, the heat transfer electrode being joined to an external heating member by a joining material and having a non-electrode region and an electrode region; a first annular sealing electrode is formed between the first sealing member and the piezoelectric diaphragm; a second annular sealing electrode is formed between the second sealing member and the piezoelectric diaphragm; a first sealing electrode and a second sealing electrode overlapping each other at the outer frame portion, the first sealing electrode and the second sealing electrode being overlapped with ... second sealing electrode and the electrode region of the heat transfer electrode being overlapped with each other at the outer frame portion, the second sealing electrode and the electrode region being overlapped with each other at the outer frame portion, the second sealing electrode and the electrode region being overlapped with each other at the outer frame portion, the

2. 2. The laminated piezoelectric vibrator according to claim 1, a first sealing electrode and a second sealing electrode, the first sealing electrode and the second sealing electrode being annularly overlapped on the outer frame portion ... second sealing electrode and the electrode region of the heat transfer electrode being annularly overlapped on the outer frame portion.

3. A piezoelectric vibrator device comprising the stacked piezoelectric vibrator according to claim 1, A piezoelectric vibration device characterized in that the external heating member consists of an oscillation IC or a heater IC, and is joined to the outer surface of the laminated piezoelectric vibrator with a bonding material while spanning both the non-electrode area and the electrode area of ​​the heat transfer electrode.

4. 4. The piezoelectric vibration device according to claim 3, A piezoelectric vibration device, characterized in that the laminated piezoelectric vibrator is laminated and sandwiched between the oscillation IC and the heater IC.

5. 4. An oven-controlled piezoelectric oscillator comprising the piezoelectric vibration device according to claim 3, The piezoelectric vibration device is hermetically sealed inside a heat-insulating package, a core portion including at least the oscillation IC, the laminated piezoelectric vibrator, and the heater IC, and at least one of the oscillation IC and the heater IC is laminated on an outer surface of the laminated piezoelectric vibrator; 2. The oven-controlled piezoelectric oscillator according to claim 1, wherein the core portion is mounted on the package via a substrate, and a space is provided between the substrate and an inner bottom surface of the package.

6. 6. The oven-controlled piezoelectric oscillator according to claim 5, the substrate is mechanically bonded to the inner bottom surface of the package by a bonding material at both ends of the substrate; 4. The oven-controlled piezoelectric oscillator according to claim 1, wherein the core portion is electrically connected to the package by a wire.

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